A cargo sled with a mass of $4.0$ kg, made from a durable composite material, is positioned on a frictionless aluminum incline at a $30$-degree angle. It is connected through a smooth, lightweight pulley to a vertically hanging steel crate that weighs $6.0$ kg. The crate starts $1.0$ meter above the ground. Find the speed of the sled and crate just before the crate hits the ground using energy conservation methods.

• A. $1.9\ \frac{m}{s}$
• B. $2.8\ \frac{m}{s}$
• C. $3.5\ \frac{m}{s}$
• D. $4.9\ \frac{m}{s}$